Abstracts

The encephalopathic epilepsies after infancy represent a difficult and frustrating management population. This pediatric population is characterized by developmental delay and frequent seizures of mixed seizure types and include specific disorders such as Lennox Gastaut syndrome (LGS).
The vagus nerve stimulator (VNS) was approved for the treatment of refractory partial onset seizures in patients 12 years and older. There have been reports of younger patients responding and with all seizure types.
We reviewed our experience in the encephalopathic epilepsies to assess better efficacy in this population..
A total of 33 patients were implanted with the VNS through the pediatric epilepsy program at Virginia Commonwealth University Health Systems. Of these, 15 patients were identified with encephalopatic epilepsy. 8 patients were diagnosed with LGS, 2 with astatic myoclonic epilepsy (Doose Syndrome) and 5 not fitting any clear syndromic diagnosis but had developmental delay, mixed seizures and complex electrographic features.
Charts were reviewed for age, gender, pre and post implant medications, seizure counts pre and post implant, seizure duration, post-ictal duration, and Quality of Life interview including alertness, interactiveness, mood changes, cluster seizures, memory and school performance.
In our series we had 7 males and 8 females. All patients had been on at least 5 antiepiletic drugs with 4 also having been on the ketogenic diet. The average age of the patient at time of implant was 11.7 years with a range of 3-21 years. The average length of the VNS implantation was 1.8 years with a range of .5-4.5 years. The majority of the patients were experiencing atonic, atypical absence, generalized tonic-clonic and complex partial seizures. 3 patients had a [ge]25% reduction in seizures, 11 with [ge]50% reduction, of which 10 had a [ge] 90% reduction, and 1 was seizure free. In 1 patient there was no decrease in seizure count. 4 of the patients who had [ge] 90% reduction did start having an increase in seizure frequency but remained at [ge] 50% reduction. Seizure reduction occurred independent of seizure type. No one seizure type appeared more or less responsive to VNS. The parent/caregiver for all 15 patients when interviewed regarding Quality of Life said that seizures were shorter in duration, the post-ictal period was reduced to under 5 minutes and perceived the patient to be more active and alert. Several of the patients were able to have a reduction in the number of AED[apos]s or the dosage they took.
The encephalopathic eplepsies are very difficult to manage with frequent intactable seizures. In our series of 15 patients VNS treatment was highly effective.This effect was independent of gender and age. Efficacy was appreciated in all seizure types. Families perceived and increase in alertness in all patients. The device was well tolerated. and medication adjustments were able to be made. In all patients independent of seizure control a dramatic reduction in post-ictal period was appreciated.